For the most part, IWB carry is much better at concealing a handgun than OWB. There are so many variables at play including the particular gun and body type, that play a huge role in what works for each person. I think body type has a lot to do with what works. If you cut yourself in two at your belt line, your body would be shaped in a few different ways. You could be a circle, on oval or a flat oval. People with a rounder shape can wear a gun at the 3:00 position with better concealment than someone with a flat oval shape. On a flat oval, the grip on all but very compact guns will print from that location. Being a flat oval myself, I carry at about 4:00 - 4:30 which dictates a holster with more muzzle rear rake to it, allowing a me to index my weapon without breaking my wrist.
For me in that position IWB, I have found nothing that comes close to a Brommeland MaxCon V. Its thin, it stays open without a thick mouth band, its comfortable and its one of the nicest pieces of craftsmanship you will find anywhere.
Good luck with your search.